The group she established was part of a wider trend which mushroomed after the October 2014 disappearance of 43 students from Ayotzinapa in the southwestern state of Guerrero.

Frustrated by a lack of government help, groups of families began their own searches for people who had disappeared in their areas, taking courses in forensic anthropology, archaeology, law, buying caving equipment and becoming experts in identifying graves and bones.

There are now at least 13 of these groups across the country.

Image copyrightAFPImage captionOn Thursday mothers held a protest in Mexico city holding portraits of their missing sons during an anti-government march.

The administration of former President Felipe Calderón (2006-2012) militarised the Mexican security forces to fight the drug cartels.

In 10 years, the so-called war on drugs he launched left tens of thousands of murder victims with numbers varying widely between civic institutions and government figures.

The International Institute for Strategic Studies (IISS) issued its annual survey of armed conflict on Tuesday, saying that 23,000 people had died in Mexico in armed conflict in 2016